The present invention relates to a device on a hand power tool for driving impact and/or drilling tools, as well as to a tool and a tool holder used for such a device.
German reference DE-OS 25 51 125 discloses a device of the above mentioned type, in which in the receiving opening of a tool holder two opposite drive strips are provided and engage in corresponding drive grooves in the shaft of the tool used in the device. Moreover, two locking bodies which are also located opposite to one another but are offset relative to the drive strips by substantially 90.degree. are provided. They engage radially in corresponding elongated troughs in the tool shaft and the axially displaceable tool, for example an impact drill or a chisel is secured against falling out or unintentional withdrawal.
Since this insertion system which is known as "SDS-plus" is used for impact drills and hammer drills as well as for the tools inserted in them and having different power, a uniform shaft diameter of approximately 10 mm is provided for the required compatibility of different tools. This however has the disadvantage that the high power tools in corresponding high power machines can be used only to a limited extent for a continuous operation, since the drivers are worn out fast. Then the torque transmission is performed only through two relatively small, opposite flanks of the drive grooves and the drive strips known also as drivers.